Very quietly, a civil war is brewing within the education reform movement over a single issue: Evaluations for teachers at charter schools.

Some point to the release of a paper called “The Hangover” in September 2012, sponsored by the American Enterprise Institute, a libertarian think tank that advocates for broad reform, as one of the first signs of this growing dispute going public. The paper showed that following the release of a 2009 report called “The Widget Effect”, which concluded that the current teacher evaluations were ineffective because they graded 99 percent of teachers as satisfactory, there was significant pressure to make teacher reviews more stringent.

That became official federal policy when the Obama administration called for statewide teacher evaluation guidelines, based in part on student performance, while soliciting for Race To The Top in 2009 and then No Child Left Behind waiver applications in 2011.

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A number of states, such as Delaware and South Carolina, used that impetus to create statewide teacher evaluation systems, bringing all schools—including charter schools—under one uniform system. State-mandated teacher evaluations create various problems, but they are particularly challenging for charter schools, according to AEI and those who advocate for more charter schools. Here is a key passage from “The Hangover” on that specific issue*:

“Charter schools are independent public schools of choice that, in many states, are granted broad flexibility from regulatory requirements in exchange for accountability,” the authors wrote. “New state teacher evaluation policies, by mandating teacher evaluations that meet certain parameters, could infringe on charters’ historical freedom in personnel matters.”

Some experts saw the paper’s comments on charters as an attempt to walk back the push for more aggressive teacher evaluations once reformers realize they could impede the progress of charter schools.

“Reformers are really caught in the uncomfortable position of arguing for new teacher evaluation approaches,” says Preston Green, an education law professor at Penn State University, “but then trying to distinguish charters from public schools. It’s become one of the unintended consequences of reform.”

Put simply, a mandated teacher evaluation system upends the entire notion of charter school autonomy. Charter schools are supposed to have complete authority within their walls—authority to hire, fire and otherwise evaluate teachers as they see fit without outside requirements—in exchange for being held accountable for their students’ success. If a charter school can’t prove success, it can be closed much more easily than a traditional public school.

That’s the deal, says Michael Petrilli, executive vice president at the Thomas B. Fordham Institute, a conservative education think tank and former official with the U.S. Department of Education during the George W. Bush administration. The idea of top-down teacher evaluation mandates violates the terms of that deal.

“This attempt to micromanage teacher evaluations from the state level really cuts against that autonomy. Having this one-size-fits-all approach is really a bad way to go,” Petrilli says. “It’s taken a little while for the charter school movement to wake up to this threat. This shows you that the school reform movement is not monolithic.”

But they’re waking up now, and the fight between advocates for teacher evaluations and charter schools is moving from the theoretical think tank world to the realm of actual policymaking. One of the best examples is the dispute between the state of New York and the Northeastern Public Charter Schools Network, which represents many of the state's charter schools, over the state’s Race To The Top application.

As part of its application, which brought $700 million in federal funds into the state, New York promised the Obama administration that it would collect teacher ratings (i.e. evaluations) from all of its public schools, including charter schools. Charter schools were allowed to use their own evaluation system, but they had to provide the results to the state education department. Charters could also decide whether they wanted to participate in the program or not—though if they didn’t, they wouldn’t be able to access the Race To The Top money. Two-thirds of New York charter schools elected not to participate.

But then at the end of last year, state officials tried to go after the non-participating charter schools’ teacher ratings as well, according to an internal memo. Charter school advocates made a strong  push for schools to ignore the state’s demands. There are a lot of New York-specific intricacies to the debate—namely, the state's Race To The Top application didn't change the existing charter school law regarding teacher evaluations and the state's education department authorizes many of the state's charter schools—but it is a microcosm of the larger debate.

It crystallizes on one specific issue: Some New York charter schools have teacher evaluation systems that are incompatible with the state system. If they were to provide the state with teacher evaluation data, they would either have to manufacture data or change their system entirely to align with the state's. That would undermine their independence as charter schools, says Bill Phillips, president of the Northeastern Charter Schools Network.

“This is about whether or not the state can force their system on the charters,” Phillips says. "It's really important to remember the charter model is: We give you more autonomy for greater accountability, so therefore we're just not going to take their instruction. That's totally foreign to our accountability process."

The charter association and state officials have exchanged numerous memos over the issue, with little sign of reconciliation. Phillips expects the state might try to force the issue when charter schools authorized by the education department are up for renewal, requiring them to adopt the state's teacher evaluation system. That, Phillips says, "would invite litigation. I think that's going to be difficult for them."

In a few states, the issue has been resolved more peacefully—Pennsylvania, for example, simply exempts charter schools from its new teacher evaluation program—but the debate is expected to continue. The newly unveiled U.S. Senate bill to replace NCLB contains similar language on teacher evaluations as the Obama administration’s NCLB waiver program, which means more states could move to state-mandated teacher evaluation standards.

So expect continued conversations about whether charter schools should be exempted from evaluation standards placed on traditional schools, experts say. It is quickly becoming one of the defining issues of the education reform movement. How the debate shakes out could have long-lasting consequences for both charter schools and teacher evaluations.

*This story has been updated, at the authors' request, to reflect that "The Hangover" covers the teacher evaluation issue more broadly than charter schools. Click through the above link to read the paper in full.